Vikunja displays blank screen behind reverse proxy (Apache)

Using the default Apache config provided (servername set to sub.domain.tld), I am unable to access Vikunja through the web frontend. The API is properly configured, as I can use the desktop app. The API is also configured with the frontend url, and the config.json in the frontend directory (compiled, not from git) has the sub.domain.tld url for the API. Below are the errors displayed in the browser:

InstallTrigger is deprecated and will be removed in the future. constants.js:50:14
Failed to get subsystem status for purpose 
Object { rejected: true, message: Error }
content-script.js:95:21
The stylesheet https://sub.domain.tld/css/app.4be21792.css was not loaded because its MIME type, “text/html”, is not “text/css”. sub.domain.tld
The stylesheet https://sub.domain.tld/css/chunk-vendors.19d758a1.css was not loaded because its MIME type, “text/html”, is not “text/css”. sub.domain.tld
The script from “https://sub.domain.tld/js/app.21baf102.js” was loaded even though its MIME type (“text/html”) is not a valid JavaScript MIME type.
sub.domain.tld
The script from “https://sub.domain.tld/js/chunk-vendors.ab7a8201.js” was loaded even though its MIME type (“text/html”) is not a valid JavaScript MIME type.
sub.domain.tld
Uncaught SyntaxError: expected expression, got '<'
chunk-vendors.ab7a8201.js:1:1
Uncaught SyntaxError: expected expression, got '<'
app.21baf102.js:1:1
The resource at “https://sub.domain.tld/fonts/open-sans-v15-latin-700italic.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/open-sans-v15-latin-italic.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/quicksand-v7-latin-300.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/quicksand-v7-latin-500.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/quicksand-v7-latin-700.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/open-sans-v15-latin-regular.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/open-sans-v15-latin-700.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld
The resource at “https://sub.domain.tld/fonts/quicksand-v7-latin-regular.woff2” preloaded with link preload was not used within a few seconds. Make sure all attributes of the preload tag are set correctly. sub.domain.tld

I have noticed that nothing under the /assets path is accessible.

Additional details:
Host OS: Raspberry Pi 4B 4GB armv6 (32-bit)
Protection: Cloudflare (proxied)
Install type: From armv6 zip on download page (non-docker)
Client: Firefox, Linux Mint

I currently do not have access to view the localhost page directly, I am dependent upon my reverse proxy to view the site remotely.

Can you share your config?

Where did you get that? That’s not used anymore.